
<h3>3proxy Perl Compatible Regular Expressions (PCRE) plugin</h3>

This filtering plugin can be used to create matching and replace
rules with regular expressions for client's request, client and
servers header and client and server data. It adds 3 additional
configuration commands:

<pre>
pcre TYPE FILTER_ACTION REGEXP [ACE]
pcre_rewrite TYPE FILTER_ACTION REGEXP REWRITE_EXPRESSION [ACE]
pcre_extend FILTER_ACTION [ACE]
pcre_options OPTION1 [...]
</pre>
pcre - allows to apply some rule for matching
<br>pcre_rewrite - in addition to 'pcre' allows to substitute substrings
<br>pcre_extend - extends ACL of the last pcre or pcre_rewrite comand by
adding additional ACE (like with allow/deny configuration commands).
<br>pcre_options - allows to set matching options. Awailable options are:
PCRE_CASELESS,
PCRE_MULTILINE,
PCRE_DOTALL,
PCRE_EXTENDED,
PCRE_ANCHORED,
PCRE_DOLLAR_ENDONLY,
PCRE_EXTRA,
PCRE_NOTBOL,
PCRE_NOTEOL,
PCRE_UNGREEDY,
PCRE_NOTEMPTY,
PCRE_UTF8,
PCRE_NO_AUTO_CAPTURE,
PCRE_NO_UTF8_CHECK,
PCRE_AUTO_CALLOUT,
PCRE_PARTIAL,     
PCRE_DFA_SHORTEST,
PCRE_DFA_RESTART,
PCRE_FIRSTLINE,
PCRE_DUPNAMES,
PCRE_NEWLINE_CR,
PCRE_NEWLINE_LF,
PCRE_NEWLINE_CRLF,
PCRE_NEWLINE_ANY,
PCRE_NEWLINE_ANYCRLF,
PCRE_BSR_ANYCRLF,
PCRE_BSR_UNICODE

<ul>
<li>TYPE - type of filtered data. May contain one or more
(comma delimited list) values:
 <ul>
 <li>request - content of client's request e.g. HTTP GET request string.
(known problem: changing request string doesn't change IP of the host to connect)
 <li>cliheader - content of client request headers,  e.g. HTTP request header.
 <li>srvheader - content of server's reply headers, e.g. HTTP status and headers.
 <li>clidata - data received from client, e.g. HTTP POST request data
 <li>srvdata - data received from server, e.g. HTML page
 </ul>
<li>FILTER_ACTION - action on match
 <ul>allow - allow this request without checking rest of the given type
of the rules
 <li>deny - deny this request without checking rest of the rules
 <li>dunno - continue with the rest of rules (useful with pcre_rewrite) 
 </ul>
<li>REGEXP - PCRE (perl) regular expression. Use * if no regexp matching
required.
<li>REWRITE_EXPRESSION - substitution string. May contain perl-style
substrings
(not tested) $1, $2. $0 - means whole matched string. \r and \n may be used
to insert new strings, string may be empty ("").
<li>ACE - access control entry (user names, source IPs, destination IPs,
ports, etc), absolutely identical to allow/deny/bandlimin commands.
Regular expression is only matched if ACL matches connection data.
Warning:
reqular expression doesn't require authentication and can not replace
authentication and/or allow/deny ACLs.
</ul>


<h4>Example:</h4>
<pre>
plugin PCREPlugin.dll pcre_plugin
pcre request deny "porn|sex" user1,user2,user3 192.168.0.0/16
pcre srvheader deny "Content-type: application"
pcre_rewrite clidata,srvdata dunno "porn|sex|pussy" "***" baduser
pcre_extend deny * 192.168.0.1/16
</pre>

<h4>Download:</h4>
<ul>
 <li>Plugin is included into 3proxy 0.6 binary and source distribution
 <li>Example configuration (by Dennis Garber): <A HREF="NoPornLitest.cfg.txt">NoPornLitest.cfg</A>
</ul>

